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. Author manuscript; available in PMC: 2010 Apr 9.
Published in final edited form as: J Autoimmun. 2008 Oct 11;31(4):362–371. doi: 10.1016/j.jaut.2008.08.007

Figure 2. Rabbits immunized with EBNA-1 peptides containing PPPGRRP develop autoantibodies.

Figure 2

(A) Immunized rabbits were tested for serum antibody binding to purified Sm by ELISA. The antibody titer in the sample date with the highest binding for each rabbit is shown. Rabbits 50, 51, 61 and 66 were immunized with PPPGRRP-MAP peptide (solid bars) and rabbits 64 and 65 were immunized with the EBNA-1 C-terminal fragment (striped bars). (B) Four out of six rabbits were positive for anti-Sm/nRNP by ELISA, including 50% of the PPPGRRP-immunized animals and both EBNA-1 C-terminal fragment-immunized rabbits. The antibody titer at the sample with the maximum absorbance value for each rabbit is shown. (C) Anti-nuclear antibodies (ANA) were detected using immunofluorescence. The maximum ANA titer for each PPPGRRP-immunized rabbit is shown. (D–F) Antibodies from immunized rabbits exhibited characteristics of molecular mimicry. Antibodies binding to PPPGRRP were purified from PPPGRRP and EBNA-1 C-terminal fragment-immunized rabbits and pre-incubated with purified Sm and nRNP before testing for binding to purified Sm (D), Sm/nRNP (E) and EBNA-1 (F). Binding of these antigens by PPPGRRP-specific antibodies, as well as inhibition of binding after pre-incubation demonstrates cross-reactivity between PPPGRRP antibodies and autoantibodies.